The program involves three major research areas: 1. the mechanism of bone resorption and bone formation and factors influencing their enhancement or inhibition. Major emphasis is being placed on the isolation and identification of the bone resorption stimulating factor(s) from human gingiva and its site of action; 2. the use of various chemotherapeutic agents in the treatment and/or prevention of periodontal disease in animals; 3. the use of bone-seeking radionuclides to study the pathogenesis of periodontal disease in beagles and to correlate external scanning data with clinical radiographic and histological alterations.